Apriltags

OpenMV Products
1

Hi.
I am benchmarking the H7 and H7plus boards equipped with the OV7725 sensor because I have an application that requires the highest possible fps.
The IDE updated the firmware of both boards to 3.6.4
I need an image VGA and Grayscale for one part of the program and also need to detect Apriltags from the same image.
To detect the Apriltags, I made a copy of the VGA image to QQQVGA
The program is as above:

import sensor, image, time

sensor.reset()
sensor.set_pixformat(sensor.GRAYSCALE)
sensor.set_framesize(sensor.VGA
sensor.skip_frames(time = 2000)
sensor.set_auto_gain(False)
sensor.set_auto_whitebal(False)
clock = time.clock()

while(True):
clock.tick()
img = sensor.snapshot().copy((0, 0, 640, 480), 0.125 ,0.125)
img.find_apriltags()
print(clock.fps())

I was expecting a higher fps with the H7plus board but, instead, with the H7 board I got 30 fps and with the H7plus board I got 15 fps.
What am I doing wrong?
Is there any way of going beyond?
Thank you for your help.

2

The H7 Plus board has external RAM which is slower than on chip RAM. The extra RAM is useful for high res applications. It doesn’t have more performance than the regular system.

Anyway, run this script:

https://github.com/openmv/openmv/blob/master/scripts/examples/35-Readout-Control/apriltag_tracking.py

It uses a method called readout control which gives you the ability to track one tag at a high resolution.

3

Thank you